While cellular coverage has improved significantly over the years, it is not uncommon to encounter areas of travel where, for often unknown reasons, cellular coverage is poor or even absent altogether. Drivers may come to recognize the existence of these areas, and may take steps to avoid them. However, it is not always possible to know where these areas exist in advance. Also, it is sometimes inconvenient to route around these areas, even if the dead zone is known to be present, if a driver is unfamiliar with the surrounding roads.